Internally located return electrode electrosurgical apparatus, system and method
A bipolar, plasma-generating electrosurgical apparatus and system wherein the return electrode is enclosed within an electrosurgical shaft, and the active electrode is located on the outside surface of the shaft such that in treating the tissue, the tissue is exposed to plasma generated on the active electrode, but is minimally exposed to electric fields generated between the active and return electrodes. Due to the configuration of the electrodes, electric fields generated between the electrodes are directed away from the target tissue and inwardly towards the return electrode within the shaft, thereby electrical stimulation of neuromuscular structures in the tissue by the electric fields is minimized.
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This invention pertains to an electrosurgical apparatus, system and method of treating body tissue, in particular a bipolar, plasma-generating electrosurgical apparatus and system wherein the return electrode is enclosed within an electrosurgical shaft, and the active electrode is located on the outside surface of the shaft such that in treating the tissue, the tissue is exposed to plasma generated on the active electrode, but minimally exposed to localized electric fields generated between the active and return electrodes. In various embodiments, due to the configuration of the electrodes, the electric fields are directed away from the target tissue, as they are oriented inwardly towards the return electrode within the shaft, thereby avoiding electrical stimulation of neuromuscular structures in the tissue by these electric fields.
BACKGROUND Electrosurgical instruments and systems comprising an active and return electrode and powered by a radio-frequency voltage supply as is illustrated for example in
In an electrosurgical system as illustrated in
Also in an electrosurgical system as is illustrated in
Accordingly, there is a need for apparatus and systems for use in electrosurgical procedures wherein unwanted electrical stimulation of the tissue is avoided, and which can be used in confined spaces within the body.
SUMMARY OF THE INVENTIONThe present electrosurgical apparatus in one embodiment comprises an electrosurgical shaft having a proximal end portion and a distal end portion. The shaft includes an active electrode disposed on the surface of the distal end portion, and a return electrode disposed within the distal end portion of the shaft. Positioned between the active and return electrode is an insulating member that prevents direct electrical contact between the active and return electrodes. The shaft includes an interconnecting passageway within the distal end portion of the shaft between the active and return electrode. The electrodes are connected to a radio-frequency voltage supply by connectors such that on applying a radio-frequency voltage difference across the active and return electrodes, plasma is generated on the active electrode, and electrical fields generated between the electrodes are directed from the active electrode to the return electrode in the shaft, to avoid electrical stimulation of the tissue. The plasma can be used to treat the tissue by coblating, heating, ablation, coagulation, cutting, removal, puncturing, probing, and otherwise stimulating the tissue.
The present electrosurgical system in one embodiment is a system for performing an electrosurgical procedure on a body tissue using plasma such that electrical stimulation of the tissue is minimized, the system comprising: an electrosurgical instrument comprising a shaft; an electrically conductive fluid supply having a discharge port on a distal end of the shaft; and a radio-frequency voltage supply connected to the electrosurgical instrument. In one embodiment, the shaft comprises: an active electrode on the distal end; a return electrode recessed within the shaft; an electrical insulator separating the active and return electrode. Within the shaft is a chamber in communication with the active and return electrodes such that on applying the radio-frequency voltage supply to the active and return electrodes in the presence of an electrically conductive fluid, plasma is generated on the active electrode on the surface of the shaft, and electric fields generated between the active and return electrodes are directed within the shaft, and thus away from the tissue.
The present electrosurgical method in one embodiment is a method of treating tissue that avoids nerve stimulation, comprising the steps of: positioning a distal end of an electrosurgical instrument in close proximity to the tissue, the distal end comprising an active electrode and a return electrode; applying a radio frequency voltage across the active and return electrodes in the presence of an electrically conducting fluid sufficient to generate plasma on the active electrode; and contacting the tissue with the plasma such that the tissue is exposed to plasma but minimally exposed to electric fields generated between the active electrode and the return electrode.
In various embodiments the present apparatus and system can be used in procedures for treating highly neutralized tissue, and other tissues located in confined targets within the body. An example of such targets is tissue in the intervertebral discs.
Details of embodiments of the present apparatus, system and methods are illustrated and described the following Figures and specifications.
BRIEF DESCRIPTION OF THE DRAWINGS
With reference to
A bipolar electrosurgical apparatus, as is illustrated for example in
Examples of an electrically conductive fluid include isotonic saline, a conductive gel, Ringer's solution and the biocompatible electrolytes as described for example in U.S. patent application Ser. No. 10/661,118, (Attorney Docket no. A-21-1), supra.
In a bipolar electrosurgical apparatus as is illustrated for example in one embodiment in
In both bipolar and monopolar plasma-generating apparatus, however, regardless of how the conductive pathway is established between the electrodes, for the instrument to generate plasma it is necessary to maintain a closed electrical circuit on the distal end of the shaft comprising the electrodes, the electrically conductive fluid and the power supply, as described for example in U.S. patent application Ser. No. 10/661,118, (Attorney Docket no. A-21-1), supra.
On a bipolar plasma-generating systems and apparatus as illustrated in
On a plasma-generating bipolar apparatus, in order to generate and use plasma to treat the tissue, the electrodes are designed such that only the active electrode generates the plasma, and that in use this electrode is located as close as possible to the target tissue. Conversely, the return electrode is designed such that it does not generate plasma, and that in use it is away from the target tissue to avoid contacting the tissue, but it is in electrical contact with the active electrode through the electrically conductive fluid. One way by which the plasma is generated on the active electrodes but not on the return electrode is to maintain the surface area of the active electrode smaller relative to the surface area of the return electrode.
In this regard it should be noted that during use, ablated tissues and other materials may accumulate on the return electrode thereby causing a reduction of its exposed surface area relative to the exposed surface area of the active electrode, thereby undesirably causing the return electrode to also generate plasma.
In a plasma-generating bipolar apparatus and system as is illustrated for example in
Also as is illustrated for example in
In procedures requiring a conductive fluid, this fluid can be provided by a fluid supply lumen located on the shaft. In this arrangement the fluid supply lumen is attached to a conductive fluid supply at the proximal end, such that the fluid is available for discharge at the distal end through an opening in the lumen near the electrodes and the target site.
Further, in a plasma-generating bipolar apparatus as is illustrated for example in
One procedure wherein a bipolar, plasma-generating apparatus is used for treating tissue is in treating an intervertebral disc as is described for example in U.S. patent application Ser. No. 10/656,597, (Attorney Docket No. S-12) incorporated herein by reference herein for all purposes. In one procedure as illustrated in
As can be appreciated in the art in using a bipolar apparatus in treating a 10 intervertebral disc as is illustrated in
Also as can be appreciated by one ordinarily skilled in the art, in treating tissue in confined spaces such as in the intervertebrate disc, it can be difficult to avoid contacting the tissue with the return electrode thus causing a short circuit across the electrodes or reducing the surface area of the electrode relative to the area of the active electrode.
Another problem with using a bipolar apparatus in confined spaces such as in the invertebrate disc is that since the shaft may include a fluid supply lumen and an aspiration lumen, the shaft can get too bulky for easy access and use.
Accordingly, the present apparatus, system and apparatus in various embodiments are adapted to electrosurgically treat tissue, while minimizing exposure of the tissue to electrical stimulation. The apparatus, as will be appreciated from the present description, is also reduced in size in part because of the placement of the return electrode with the shaft; thus, with a smaller profile on the distal end the present apparatus and system provides improved access flexibility for applying electrosurgical procedures in restricted areas of the body, as for example, within an intervertebral disc.
With reference to
In one embodiment the electrosurgical apparatus comprises a lumen (70) within the shaft through which an electrically conductive fluid such as saline, Ringer's solution or an other acceptable other biocompatible ionic solutions can be supplied to the distal end of the shaft in the vicinity of the electrodes and the target tissue. As is illustrated in
In the embodiment illustrated in
In an embodiment of the active electrode illustrated in
Also in the embodiment of the apparatus illustrated in
With reference to
Also provided in the present application is a system for performing an electrosurgical procedure on a body tissue using plasma, as is illustrated for example in
Further provided is a method of treating body tissue including nerve-sensitive tissue in the body, as set forth in
By the present description and Figures it is to be understood that the terms used herein are descriptive rather than limiting, and that changes, modifications, and substitutions may be made without departing from the scope of the invention. Also it will be appreciated that although the present apparatus, system is described in the context electrosurgery on an intervertebral disc, the apparatus and its use is not restricted to treating discs but is applicable in general for electrosurgical procedures wherein is desired to minimize exposure of the tissue to electrical stimulation, and where access to the tissue is limited. Therefore the invention is not limited to the embodiments described herein, but is defined by the scope of the appended claims.
Claims
1. An electrosurgical apparatus comprising:
- a shaft having a proximal end portion and a distal end portion;
- an active electrode disposed on the surface of the distal end portion of the shaft;
- a return electrode disposed within the distal end portion of the shaft;
- an insulating member positioned on the distal end portion of the shaft and preventing direct electrical contact between the active and return electrodes; and
- electrical conductors adapted for applying a radio-frequency voltage difference across the active and return electrodes,
- wherein the active electrode and return electrode define an interconnecting passageway within the distal end portion of the shaft.
2. The electrosurgical apparatus of claim 1, wherein the return electrode comprises a lumen within the shaft.
3. The electrosurgical apparatus of claim 2, wherein the lumen and the interconnecting passage way comprises a continuous fluid conduit within the shaft.
4. The electrosurgical apparatus of claim 3, wherein the lumen is adapted for conveying an electrically conductive fluid into the interconnecting passageway at the distal end of the shaft.
5. The electrosurgical apparatus of claim 4, wherein the lumen is adapted for receiving electrically conducting fluid at the proximal end portion of the shaft.
6. The electrosurgical apparatus of claim 4, wherein the electrically conductive fluid is selected from the group consisting of isotonic saline, Ringer's solution and other biocompatible ionic solutions.
7. The electrosurgical apparatus of claim 1, wherein plasma is generated on the active electrode upon application of the radio-frequency voltage across the active and return electrodes in the presence of an electrically conductive fluid.
8. The electrosurgical apparatus of claim 1, wherein an electric field is generated upon application of the radio-frequency voltage across the active and return electrodes, and wherein the electric field is directed from the active to the return electrode in the shaft.
9. The electrosurgical apparatus of claim 1, wherein the active electrode comprises one or more aperture therethrough for passing an electrically conductive fluid between the outside of the shaft to the return electrode.
10. The electrosurgical apparatus of claim 1, wherein the return electrode comprises a conductive cap exposed on the outer surface of the shaft, wherein the cap is spaced sufficiently from the active electrode to minimize generation of an electric arc between the active electrode and the cap.
11. The electrosurgical apparatus of claim 1, wherein the distal end of the shaft is sized for insertion into an intervertebral disc of a patient.
12. The electrosurgical apparatus of claim 1, wherein the shaft comprises an aspiration lumen having an inlet in the proximity of the electrodes for removing fluids form the distal end portion of the shaft.
13. An electrosurgical instrument for treating tissue within a body, comprising:
- a shaft having a proximal end portion and a distal end portion;
- an active electrode comprising a tissue-contacting surface on the distal end portion of the shaft;
- a return electrode recessed within the tissue-contacting surface; and
- an insulator separating the active and return electrodes,
- wherein the tissue-contacting surface is adapted for generating plasma upon application of a radio frequency voltage across the active and return electrode in the presence of an electrically conducting fluid.
14. The instrument of claim 13, wherein the tissue-contacting surface and the return electrode define a chamber within the distal end portion of the shaft.
15. The instrument of claim 13, wherein the shaft comprises a fluid discharge lumen having a discharge port into the chamber.
16. The instrument of claim 13, wherein the shaft comprise a suction lumen having a suction port from the chamber.
17. The instrument of claim 13, wherein the active electrode defines an opening into the chamber.
18. The instrument of claim 13, wherein active electrode at least partly surrounds the return electrode.
19. The instrument of claim 17, wherein the active electrode comprises one or more holes opening into the chamber for fluid flows between the active and return electrodes.
20. The instrument of claim 16, wherein the return electrode comprises the suction lumen.
21. The instrument of claim 13, wherein the active electrode comprises the tissue-contacting surface.
22. The instrument of claim 13, wherein the active electrode has an annular configuration around the shaft.
23. The instrument of claim 13, wherein the active and return electrodes are coupled to the radio-frequency power supply by one or more connectors.
24. The instrument of claim 13, wherein return electrode extends to a return electrode cap on the shaft at a location sufficiently spaced from the tissue-contacting surface to prevent an electrical circuit between the active electrode and the return electrode cap.
25. A system for performing an electrosurgical procedure on a body tissue using plasma, the system comprising:
- an electrosurgical instrument comprising a shaft;
- an electrically conductive fluid supply having a discharge port on a distal end of the shaft; and
- a radio-frequency voltage supply connected to the electrosurgical instrument, wherein the shaft comprises:
- an active electrode on the distal end;
- a return electrode recessed within the shaft;
- an electrical insulator separating the active and return electrode; and
- a chamber in communication with the active and return electrodes within the shaft, wherein on applying the radio-frequency voltage supply to the active and return electrodes in the presence and electrically conductive fluid, plasma is generated on the active electrode, and electric fields generated between the active and return electrodes are mostly contained within the shaft.
26. The system of claim 25, wherein the body tissue comprises an intervertebral disc.
27. The system of claim 25, wherein the conductive fluid supply comprises a fluid delivery element that forms an electrically conductive fluid path in contact with the active electrode and the return electrode.
28. The system of claim 25, wherein the distal end portion of the shaft is sized for insertion into an intervertebral disc.
29. The system of claim 25, wherein the active electrode comprises a portion of the external surface of the shaft.
30. The system of claim 27, wherein the fluid delivery element comprises a fluid supply lumen extending through the shaft, the fluid supply lumen comprising an inlet port into the conductive fluid supply, and a discharge port in the proximity of the active electrode.
31. The system of claim 27, wherein the fluid delivery element comprises a fluid supply instrument separate from the shaft.
32. The system of claim 25, wherein a fluid aspiration lumen for aspirating fluid from a region around the active electrode is provided for removing fluid in the vicinity of the active electrode.
33. The system of claim 32, wherein the fluid aspiration element comprises a suction lumen extending through the shaft, the suction lumen having an inlet in the vicinity of the active electrode.
34. The apparatus of claim 25, wherein the active electrode comprises one or more openings positioned over the chamber for passing electrically conductive fluid into the chamber.
35. The apparatus of claim 25, wherein an electrically insulating support member is located within the shaft for isolating the active electrode from the return electrode.
36. A method of treating nerve-sensitive tissue in the body, comprising:
- positioning a distal end portion of an electrosurgical instrument in close proximity to the tissue, the distal end comprising an active electrode and a return electrode, wherein the active electrode comprises a tissue-contacting surface on the distal end portion, and the return electrode is recessed within the tissue-contacting surface;
- applying a radio frequency voltage across the active and return electrodes in the presence of an electrically conductive fluid sufficient to generate plasma on the active electrode; and
- contacting the tissue with the plasma.
37. The method of claim 36, wherein the return electrode is enclosed within the shaft, and wherein a fluid passageway is formed within the shaft between the active electrode and the return electrode.
38. The method of claim 36, wherein the conductive fluid is in contact with the active and return electrode through the fluid passageway.
39. The method of claim 36, wherein the conductive fluid is supplied from a fluid supply lumen located on the instrument.
40. The method of claim 36, wherein the conductive fluid is selected from the group consisting of isotonic saline, Ringer's solution, and body fluids.
41. The method claims 36, wherein fluids in the vicinity of the active and return electrodes are removed by a suction lumen comprising a suction port located in the proximity of the active electrode.
42. The method of claim 36, wherein the body tissue comprises an intervertebral disc.
43. The method of claim 36, wherein treating nerve-sensitive tissue comprises coblating, heating, ablation, coagulation, cutting, removal, puncturing, probing, and otherwise stimulating the tissue.
Type: Application
Filed: Mar 2, 2006
Publication Date: Sep 6, 2007
Patent Grant number: 7879034
Applicant: ArthroCare Corporation (Austin, TX)
Inventors: Jean Woloszko (Mountain View, CA), Thomas Jenkins (Oakland, CA)
Application Number: 11/367,254
International Classification: A61B 18/14 (20060101);